The invention relates to a method for multi-track production of transdermal therapeutic patches, with a pressure-sensitive adhesive reservoir film which comprises at least one layer and contains active substance and which is arranged between a backing film and a removable protective film.
Transdermal therapeutic patches are pharmaceutical forms that are to be applied to the skin and that look like traditional sticking plasters. The patches contain at least one pharmaceutical substance that is to be released via the skin. The pharmaceutical substances are continuously released at a predetermined rate over a fixed period of time at a defined site of application on the skin of the body.
Patches of this kind generally have simple geometric shapes. For example, they are rectangular or diamond-shaped in plan view. The patch itself is composed, for example, of a film reservoir which contains active substance and which has an adhesive layer oriented toward the skin. The adhesive layer too can additionally carry pharmaceutical substance. The film reservoir is packed between a removable protective film and a backing film that adheres to the protective film. The backing film ensures that third parties cannot take in active substances upon accidental contact with the patch.
Patches of this kind have hitherto been produced using a method known from DE 41 10 027 C2 for single-track production. In said method, the reservoir film is present as a long web which is wound up into a narrow roll. The diameter of this roll is generally many times greater than the roll width. If, in order to increase the quantity produced per unit of time on a packaging machine, several of these narrow rolls are to be used next to one another for multi-track production, the web-like reservoir films, which are sticky on one side, have to be fed synchronously to the protective film, cut to length, and transferred to the packaging device. Since the film rolls in most cases have different diameters, the web-like reservoir films are subjected to different tensile stresses, which has a negative effect on the synchronization. The synchronous feed is, however, absolutely essential to ensure that no left-over material is generated on multi-use cutting of the web-like reservoir films. Left-over material containing active substance constitutes special waste that has to be disposed of separately.
The present invention therefore addresses the problem of developing a method for multi-track production in which web-like reservoir films that can be unwound from rollers can be used without generating left-over material that contains active substance.